Question: Which of these foods are said to stir passion? An oyster, and avocado or a turnip? (Scroll down to the bottom for the answer.)

One of these, at least, is a gimme. The stories linking oysters and other shellfish to lust go back to at least the ancient Greeks.

Think of the image of Aphrodite, the goddess of love, rising out of the sea from the half-shell.

"There's something primal about eating oysters," says oyster-lover MJ Gimbar. He describes them as creamy and velvety. "It's like a kiss from the ocean."

It's a good thing his passions run so deep, because part of his job as fishmonger for the Washington, D.C-region's Black Restaurant Group is to introduce newbies to the experience of oysters.

His trick: Offer up a big range of tastes. As he describes in his blog The Edible Ocean, not all oysters are salty.

During a tasting, he serves up a Kumamoto Oyster, which is sweet, almost melon-like.

Then he introduces a Barren Island Oyster, which, by contrast, is buttery and mild, with hints of a mineral-like taste. "The taste is indicative of where [the oyster] grows." Barren Island Oysters are harvested in the Chesapeake Bay.

Increasingly, fishmongers play up the equivalent of a wine terroir. "The water [where the oysters are grown] and the species all make a difference" to the taste, Gimbar says.

Now, when it comes to evoking an aphrodisiac effect? Well, if you talk to oyster-lovers like Gimbar, all oysters seem to have the potential.

"Isn't it the zinc?" diners have asked Gimbar. Well, maybe. Oysters do contain zinc. And scientists have found a link between zinc and testosterone levels.

But this is a long way from proving that eating a plate-full can stir carnal lust.

In recent years, scientists have been studying the amino acids in mollusks, including oysters.

One paper published a few years ago in the journal Animal Reproductive Science documented a link between high levels of the amino acid D-Aspartic acid and improved sperm count — in rabbits.

Now, it's not clear how much of this amino acid we're getting when we eat a plate of oysters. And the extent to which this could be true in humans begs a lot more scientific investigation.

But it's intriguing that, centuries after the Greeks made the love connection, scientists are still trying to pin down whether there's something to it.

Culinary historian Kathleen Wall of the Plimoth Plantation in Massachusetts has a different theory as to why the stories connecting love and oysters have amplified over time.

"It's perception," Wall says. "What people think about food has an effect on the body. It's the placebo effect." The stories we tell ourselves become true, she says.

She points to 17th-century Dutch paintings where scattered oyster shells are a common symbol of lust.

And how about the women who sold oysters in Colonial America? "Oyster wenches were thought to be a little loose because they were so stirred up by the proximity [to the] oysters," Wall says.

"We haven't let go of these [associations]," Wall says. And over time, they've only become stronger.

Whether it's love or lust, oysters carry their past with them.

And, oh, I won't leave you in the lurch re: the avocado and the turnip. Turns out, they've all been said to stir up, well you know, desire.

So if oysters are not in your Valentine's Day budget, hey, maybe look to that root vegetable for an affordable alternative.

Copyright 2014 NPR. To see more, visit http://www.npr.org/.

Transcript

ROBERT SIEGEL, HOST:

This is ALL THINGS CONSIDERED from NPR News.

If you're looking to make an impression on your valentine, flowers and chocolate can certainly go a long way, though maybe that's a little predictable. What about certain foods that are said to stir up passion? I'm thinking of oysters.

NPR's Allison Aubrey has this report on the links between oysters and love.

ALLISON AUBREY, BYLINE: Oysters are big in the restaurant scene, just ask fishmonger MJ Gimbar. He'll be serving up hundreds tonight at Black's Restaurant in D.C.

MJ GIMBAR: All right, so we've got four different species of oysters. The first oyster you're going to look at is the kumamoto.

AUBREY: As he wiggles his knife in and pops open the shell, he says this oyster is one of his favorites. It's small and sweet. It tastes almost like melon.

GIMBAR: Oh yeah, it's really good. I love it. The texture is kind of like a creamy, velvety - it's basically like a kiss from the ocean.

AUBREY: A kiss from the ocean, MJ says lots of diners who order oysters don't think of it as just a dish. They're after something more.

GIMBAR: There is something primal about eating an oyster. It's kind of exotic. It's almost like a sexual experience.

AUBREY: Now, MJ is certainly not the first oyster lover to make this association. Culinary historian Kathleen Wahl of the Plymouth Plantation in Massachusetts says when it comes to oysters and other shellfish, the romantic goes back at least to the Greeks.

KATHLEEN WAHL: The very origins of origins of oysters and shellfish are from Aphrodite and Eros, the Greek god and goddess of the sea rise up on shells - on the half shell, as it were. And so there's that classical connection.

AUBREY: Back then, people thought just being near oysters could help kindle desire. So the Greeks thought of oysters as a kind of fertility treatment. It sounds crazy, but to this day, scientists are still trying to see if there's something there. They've looked at the zinc in oysters, which is linked to increased testosterone and most recently have focused on the amino acids found in oysters. One researcher in Naples, Italy, Antimo Danielo(ph) who I spoke to by Skype, told me he's convinced that there's a scientific basis for an aphrodisiac effect.

ANTIMO DANIELO: Yes, yes, it is right.

AUBREY: He points to a study that found high levels of one particular amino acid found in oysters improved the sperm count of rabbits.

DANIELO: Yes, I was surprised, but I expected it.

AUBREY: Now the extent to which this could be true in humans begs a lot more investigation. Perhaps the amino acids are significant, but if this is the case, similar amino acids are found not just in oysters, but in all kinds of foods, from fish and seaweed to avocados and eggs. Are they all aphrodisiacs? Now, historian Kathleen Wahl is skeptical. She says maybe scientists have not been focused on the right thing.

WAHL: The part they're not identifying is perception. What people think about food makes that food have an effect on the body. It's the placebo effect.

AUBREY: She says look at how the narratives connecting love and oysters have amplified over the centuries. Take, for instance, 17th century Dutch paintings. Scattered oyster shells are a common symbol of lust and in colonial days, women who sold oysters, known as oyster wenches, were thought to be inviting something more than a simple transaction.

WAHL: Oyster wenches were noted to be perhaps a little easy because they were so stirred up by their mere proximity of oysters.

AUBREY: So if our belief systems are key to evoking an aphrodisiac effect, consider this, it has not always been the oyster in the romantic spotlight. At one point in history, an influential health expert recommended the turnip for its strong aphrodisiac powers.

WAHL: Turnips, yeah, turnips just was like, oh, my goodness, turnips are the Viagra of the 17th century.